Electrical and electronic circuits are often formed on planar circuit boards. Often, it is desirable to interconnect two or more circuit boards to one another in a stacked configuration. When stacking multiple circuit boards, a minimum spacing must be maintained between a first circuit board and the circuit board or boards adjacent to the first circuit board. Such spacing is required for various reasons, including the prevention of electrical shorts between the boards, and the provision of cooling airflow over components interconnected to the circuit boards.
Systems for interconnecting circuit boards include threaded fasteners in combination with spacers. In such a system, a screw (or bolt) is passed through a hole formed in a first circuit board. Next, the spacer is placed over the screw, before the end of the screw is passed through a hole formed in a second circuit board. Finally, a nut is placed over the end of the threaded fastener to secure the assembly. Although a system of threaded fasteners in combination with spacers is capable of securely fastening a first circuit board to a second circuit board, such a system is not entirely satisfactory for a variety of reasons. For instance, considerable labor is involved in piecing together and securing the assembly, thus resulting in a relatively slow and expensive assembly process.
In addition, in order to interconnect a third circuit board using such a system, additional holes must be formed in either the first or second circuit board. This is disadvantageous, as space on individual circuit boards is often at a premium. In addition, the assembly of an electrical component having more than two interconnected circuit boards creates additional assembly difficulties, as access to the fasteners used to interconnect additional circuit boards is often limited. Alternatively, stacks of three or more circuit boards may be created by interposing interior circuit boards between two spacers, and using a screw that passes through all of the circuit boards. However, the assembly process for stacking three or more circuit boards in this manner is even more difficult than stacking a pair of circuit boards.
Another system for interconnecting multiple circuit boards involves the use of threaded spacer members in connection with threaded screws (or bolts). In such a system, the screw is placed through a hole formed in a first circuit board, and is then threaded into the threaded spacer. Next, a second screw or bolt is placed through a hole in the second circuit board, and is then threaded into the opposite end of the threaded spacer. Although such a system can decrease assembly times as compared to systems using spacers having smooth bores in combination with threaded fasteners, the threading of multiple components to one another is still required. Accordingly, the interconnection of multiple circuit boards using such a system remains relatively time consuming and expensive. In addition, such a system may also require the use of additional holes in circuit boards where more than two circuit boards are attached to one another.
Snap-fit, one piece interconnects have also been used for interconnecting circuit boards. Such one piece interconnects are capable of reducing the time required to interconnect multiple circuit boards. However, such one piece interconnects must be supplied in a variety of sizes, to accommodate different circuit board thicknesses and to accommodate different spacings between interconnected circuit boards. In addition, where more than two circuit boards are interconnected, interior circuit boards must have an additional set of holes formed therein, limiting the area of the circuit board available for electrical componentry
For the reasons set forth above, there is a need for a method and apparatus for interconnecting multiple circuit boards quickly and inexpensively. In addition, there is a need for a method and apparatus that allows for more than two circuit boards to be interconnected that requires a minimal amount of circuit board area. There also is a need for a method and apparatus for interconnecting multiple circuit boards that is reliable in operation and inexpensive to implement.